1. Field of the Invention
This invention relates to a photoconductive film and an electrophotographic photosensitive member using the film, and more particularly, to an electrophotographic photosensitive member where the increase in residual potential upon repeated use is prevented.
2. Description of the Prior Art
There are known electrophotographic photosensitive members of a laminate type which comprises a conductive support, a charge generation layer principally comprising a charge generation material such as selenium, cadmium sulfide, phthalocyanine pigment, azo pigment, indigo dye, perylene series pigment, and the like and, further thereon, and a charge transfer layer principally comprising a charge transfer material such as poly-N-vinylcarbazole, phenanthrene, and the like.
Since, in particular, organic pigments and dyes as charge generation materials are easier to synthesize in comparison with inorganic materials and moreover the selectivity of the photosensitive wavelength region has been enlarged and so on, a number of organic pigments and dyes are charge generation materials have been proposed.
For instance, the laminate type electrophotographic photosensitive members using disazo pigment as disclosed in the specifications of U.S. Pat. Nos. 4,123,270, 4,247,614, 4,251,613, 4,251,614, 4,256,821, 4,260,672, 4,268,596, 4,268,547, 4,293,628, etc. are known. However, there are disadvantages that when a photosensitive member of such a multilayer construction is used repeatedly, residual electric charges are accumulated due to charge injection in the interface between the charge generation layer and the charge transfer layer, or trap in the charge generation layer resulting in low sensitivity, low resolution and fog of copy image. Therefore, in order to prevent these disadvantages, such technologies as minimizing the thickness of a charge generation layer or adding various additives to the charge generation and charge transfer layers and so on have hitherto been proposed. Even by these methods, however, the accumulation of residual electric charge is large in the laminate type photosensitive member.